The present invention relates to a cutter apparatus and a printer with a cutter apparatus.
Conventionally, there has been a printer that stores a paper roll and prints onto the paper drawn from the paper roll. Such printer is provided with a cutter apparatus to separate a printed portion, which is part of the paper that is printed, from the non-printed portion of the paper. The cutter apparatus includes a guillotine-type cutter apparatus, which includes a fixed blade made of a plate and a movable blade made of a plate reciprocating with respect to the fixed blade. Such guillotine-type cutter apparatus is disclosed in patent documents such as Japanese Patent No. 4455091 (Document 1), Japanese Unexamined Publication No. 2005-59502 (Document 2), and Japanese Unexamined Publication No. 2002-128378 (Document 3).
The movable blade of the cutter apparatus disclosed in Documents 1-3 is made of a single plate having a V-shape cutting edge gradually projecting in the advancing direction of the movable blade toward the ends of the cutting edge. The movable blade is moved toward the fixed blade opposite until the cutting edge of the movable blade slides across the cutting edge of the fixed blade to cut the paper. In this type of cutter apparatus, when the movable blade is moved toward the fixed blade, the V-shape cutting edge of the movable blade is brought into contact with the cutting edge of the fixed blade at two points, one of which is at one side and the other is at the other side in the width direction of the paper. The paper caught between the movable blade and the fixed blade is gradually cut at the two points as the movable blade is moved toward the fixed blade.
Further, another cutter apparatus including a first movable blade disposed on one side in the width direction of the paper and a second movable blade disposed on the other side in the width direction of the paper is known, as disclosed in patent documents such as Japanese Unexamined Publication No. 2009-107090 (hereinafter referred to as Document 4). The cutter apparatus disclosed in Document 4 includes the first movable blade made of a plate and the second movable blade made of a plate (hereinafter, collectively referred to as the movable blades) respectively having a straight-line cutting edge gradually projecting in the advancing direction of the movable blade toward the end of the paper in the width direction. The first movable blade and the second movable blade touch each other at the center in the width direction of the paper. When the movable blades are moved toward the fixed blade, each of the cutting edges of the movable blades is brought into contact with the cutting edge of the fixed blade at a point. The paper caught between the movable blades and the fixed blade is gradually cut at the two points as the movable blades are moved toward the fixed blade.
A notch is formed in the cutting edge of one of the movable blades at the position where the movable blades meet each other. The notch is extended toward the opposite direction to the advancing direction (hereinafter referred to as the retracting direction) of the movable blade. A portion of the paper is left uncut by the notch. The notch thus provides a partial cut. The notch has an auxiliary cutting edge at the end in the retracting direction. In this type of cutter apparatus, the movable blades are moved in the advancing direction until the auxiliary cutting edge overlaps the fixed blade to cut the uncut portion off, thus providing a full cut.
As discussed above, in the cutter apparatus of Documents 1-3, the V-shape cutting edge of the movable blade is brought into contact with the cutting edge of the fixed blade at both sides across the paper in the width direction. It is preferable that an appropriate pressure is constantly applied to both of the two points. However, since the movable blade disclosed in Documents 1-3 is made up of a single plate, the contact pressure at one point likely has an influence on the other point. For example, a variation in dimension, assembly or cutting load would influence the contact pressure, resulting in the increase in pressure at one point and the decrease in pressure at the other point. Due to the increase in pressure, part of the blade is possibly subject to wear, resulting in a shortened lifetime of the cutter. Decrease in pressure possibly results in a cut in failure.
In the cutter apparatus of Document 4, each of the cutting edge of the first movable blade and the second movable blade is independently brought into contact with the cutting edge of the fixed blade at a point. The influence of one point on the other point is therefore comparatively less, but friction force is undesirably generated at the portion where the first movable blade and the second movable blade touch each other. This friction force possibly reduces the contact pressure of the movable blades on the fixed blade. Reduction in pressure results in a cut in failure.
FIG. 5A is a schematic view of a paper partially cut by the cutter apparatus of prior art of Document 4.
In the cutter apparatus of Document 4, an uncut portion P1 is formed corresponding to the notch formed in the cutting edges of the movable blade when the movable blades are advanced toward the fixed blade. In FIG. 5A, the uncut portion P1 is represented by a dotted line. As the movable blades are further advanced, a cut P2 is formed in the printed part PP, of which depth corresponds to the thickness of the movable blade. The cut P2 is formed at the ends of the uncut portion P1 mainly by the advancing edge of the notch having a thickness of the movable blade.
FIG. 5B is a schematic view of the paper fully cut by the cutter apparatus of prior art of Document 4.
As the both movable blades are further moved after the uncut portion P1 is formed, the printed part PP is pushed in the thickness direction of the paper P, which is the advancing direction of the movable blades. Subsequently, the printed part PP is further pushed by the movable blades upward in a direction away from non-printed part PN. Being pushed upward, the printed part PP is unintentionally torn off the non-printed part PN at the ends P3 of the cut P2. This possibly occurs even when the printed part PP is only pushed in the thickness direction of the paper P.
When the printed part PP is unintentionally torn off the non-printed part PN around the ends P3 of the cut P2, part of paper is left as a protrusion P4 in the non-printed part PN. Subsequently, the protrusion P4 is separated from the non-printed part PN when the uncut portion P1 is cut by the auxiliary cutting edge. The separated protrusion, which is a flake of paper, drops inside the printer, possibly disturbing the paper conveyance and thereby causing a paper jam. Further, the flake of paper possibly enters inside the mechanism, causing a malfunction of the printer. In addition, the printed part PP discharged from the printer has a bad looking due to the lack corresponding to the protrusion P4.